centenarian

One who or that which is at least 100 years old.

The average age of these 203 centenarians was 102 years 5 months and 25 days.

He proposed the formation of the Louisiana Live Oak Association, whose members would be trees at least a hundred years old. First among the centenarians he listed was the Locke Breaux oak, the largest tree he knew, measuring 10.7 m (35 ft.) in circumference, 22.8 m (75 ft.) tall, with a spread of 50.6 m (166 ft.) in 1932.

Aged 100 years or more; extremely old.

Of or relating to centenarians or a centenary celebration.